Surgical knife



y 7, 1931- R. E. THOMPSON 3,

SURGICAL KNIFE Filed Nov. 5, 1927 IFWEIJT E! RALPH E. 'mompsorv;

Patented July 7, 1931 EE sTArss nALPI-In. rrromrson, orBROOKLI-NE,.MASACHUSETTS, ASSIGNOR T GILL TE sArErY RAZOR COMPANY, orBOSTON, massaorrusnrrs, A CORPORATION or DELAWARE SURGICAL KNIFEApplication filed. November This invention relates to knives havingremovable or replaceable blades, and more particularly to those used forsurgical work. Its purpose is to provide an improved knife of this typecomprising two separate parts only,-the handle and the blade and,furthermore, so to design these parts that they may be accurately andrigidly interlocked easily by a surgeon whose hands are encased in 19rubber gloves with little or no danger of cutting, and as readilydisengaged and separated. Consideration has also been given in thedesign of the handle-to providing a onepiece or integral constructionwhich may be quickly and thoroughly sterilized after using and, to thisend, all deep, inaccessible grooves wherein foreign matter mightaccumulate have been avoided;

The invention as herein shown is emzo bodied in a surgical knifecomprising an elongated handle having asocket formed in one side of thebody thereof and a replaceablebladehaving a shank with an enlargementadapted to fit the socket," thereby forming a defined fulcrum for'relative movement of the handle and blade. This is prevented in thedirection of cutting pressure by a rigid jaw but permitted in theopposite direction for purposes of disengaging the 7 30 blade from thehandle, as will appear. An

5 ferred embodiment thereof, selected for purposes of illustration andshown in the accompanying drawings, in which- Fig. l is a view inelevation of the complete knife;

Fig. 2 is a View in elevation, on a larger:

5, 1927. Serial a... 231,329.

scale, of the blade holding portion of the hamdle;

Fig. 3 is a similar view, partially insection, showing the blade asdisplaced as in the process of disengaging it; and Fig. 1 is a sectionalview on the line 4-4 of Fig. 2.

The elongated handle 10 of the knife is formed of thin sheet stock,smooth except adj ac'ent to its blade holding end where it is providedwith scoring 12 to facilitate grasping. It is shaped at its forward endfor interlocking engagement with the blade in the following manner. Anelongated recess is provided which terminates in a shallow socket 14;circular in outline and formed in the rigid material of thehandle.The'upper wall of the elongated recess comprises a rigid aw 16,groovedthroughout its length and enlarged somewhat at its outer end sothat the depth of the groove is greater at this point than throughoutthe rest of the jaw; The bottom of the recess comprises a web 18integral with the handle 10 and the 16, and of substantial width so thatthe jaw 16 is, to all intents and purposes, a rigid, integral part ofthe handle.

Oppositely disposed with respect to the rigid aw 16 is a spring jaw,comprising an. elongated flexible sectlon 19 and arigid, grooved bladeengaging portion 20, the

groove in this being substantially deeperthan the groove in the rigidjaw.

The yielding jaw is substantially shorter than the rigid jaw 16. Itsinner flexible section 19 is entirely out of contact with "the blade andis subject to no strains in the normal use of the knife. The outer bladeengaging portion 20 contacts with the'blade only at a point spaced fromits fulcrunrin thesocket 14 and there isaccordinglyno danger of the jawbeing bent on'a short radius and so broken.

- The blade designed to be'received by the handle above described is ofthin flexible steel, having an elongated shank 30, terminating in acircular enlargement 32, and a blade por-.

tion with a sharpened cutting edge 34-. .The

back of the. blade and shankconstitutesa t g t unbroken ge adapte a a eas and be supported by the bottom of the groove formed in the rigid jaw16 of the handle. T he circular enlargement 32 at the end of the shankis designed to fill the socket 14 in the handle and the sharpenedcutting edge terminates ust outside the point of engagement of thegrooved portion 20 of the spring aw.

It will be seen that the interlocking ofthe enlarged portion 32 of theblade with the circular. socket 14' of the handle prevents longitudinalmovement of the blade with respect to the handle and constitutes adefined fulcrum about which the only relative movement of the blade andhandle is possible. Relative movement in the direction of cuttingpressure is positively prevented by the rigid jaw 16 which overlies theback of the blade and extends to a position opposite its cutting edge.Movement in the other direction, however, is permitted in opposition tothe yielding jaw for purposes of disengaging the blade and maybeeffected by exerting pressure on the back of the blade near the pointthereof. This is suggested in Fig. 3, where the blade is shown asdisplaced away from the rigid jaw sufficiently to carry its back edgeclearof the groove therein, to permit which the lower jaw is sprungdownwardly. A very slight lateral. pressure is sufiicient to clear theback of the blade from the grooved aw 16 and the blade may be completelydisengaged from the handle unless the operator keeps one finger over thesocket 14 so as to retain the enlargement 32 of the shank therein. Ifthis is done, the blade may he carried to any point of disposal and thendropped out of the handle.

In inserting a new blade in the handle, the

. enlargement 32 is first placed in its socket 14:

and the shank of the blade carried into the deep groove of the portion20 of thespring jaw. Pressure now applied to the back edge of the bladewill displace the spring jaw sufficiently to permit the back of theblade bein slipped into the groove of the rigid jaw and the blade ismaintained in engaged and interlocked position by the spring pressure ofthe lower jaw.

Having thus described my invention, what I claim is new and desire tosecure by Letters Patent is:

1. A surgical knife comprising an integral handle having a socket in thebody thereof adjacent to one end, a replaceable blade having a shankformed with an enlargement to fit the socket, thereby anchoring theblade longitudinally and constituting a defined fulcrum point for theblade in the handle, a rigid jaw supporting the blade for more than halfits entire length, and a spring jaw substantially shorter than the rigidjaw for maintaining the blade in engagement with the rigid aw. i

2. A surgical knife comprising an integral handle having a socket formedin the body thereof, a replaceable blade having a shank handle.

with an enlargement to fit the socket, a aw supporting the blade rigidlyagainst cutting pressure, and a substantially shorter spring jawmaintaining the blade in engagement therewith while permitting it toswing about the fixed axis of said socket.

3. A surgical knife comprising a fiat handle having a circular socketformed in the body thereof, a replaceable blade having a shank with acircular enlargement at its end to fit the socket, thereby forming adefined fulcrum in the handle for relative movement of the handle andblade, a rigid jaw engaging the back edge of the blade opposite to itscutting edge and a spring jaw engaging the other edge at a point shortof its cutting edge.

4. A surgical knife comprising a handle having at one end a jaw with arigid supporting edge, a replaceable blade having a co-' operating edgeadapted to be engaged by the jaw and a pivotal connection with thehandle, and an oppositely disposed spring jaw cut away so as to engagethe blade only at a point remote from its inner end, and permit theblade to yield to a pressure exerted obliquely on the back thereof toeffect disengagement of the blade and handle.

5. A knife comprising a handle having at one end a rigid grooved upperjaw and a socket independent of said jaw, a blade having an enlargementat its inner end to fit the socket thereby determining its fulcrum formovement away from the upper jaw, and a lower spring jaw cut away so asto engage the blade only at a point remote from such fulcrum and permitdisengagement of the blade from the handle by pressure exerted obliquelyon the back of the blade.

6. A knife comprising a handle having a shallowsocket in its bodyportion and a rigid grooved upper jaw projecting outwardly beyond thesocket, a removable blade having an enlargement shaped to turn in thesocket in the body of the handle and prevent longitudinal displacementof the blade, and a lower spring jaw acting to hold the blade in thegroove of the upper jaw but permitting it to be forcibly disengagedtherefrom while maintaining its connection with the socket of the RALPHE. THOMPSON.

